If the gas was empty for three days, the furnace may have attempted to start numerous times causing virtually ALL residual gas in the incoming line to be drawn out. You may consider purging the gas line at the clean out cap where the gas line enters the furnace. However, it should have restarted and stayed running after just a few times at the most because as long as the line was NOT disconnected from the main tank, there should be NO air inside the line to cause flame failure.
I'd suggest asking the service company to double check the furnace manifold pressure to ensure there is not a regulator related problem.
Three times this winter (on the coldest days no less) a tiny droplet of water froze internally of the regulator right on the orifice blocking gas flow.
Answers & Comments
If the gas was empty for three days, the furnace may have attempted to start numerous times causing virtually ALL residual gas in the incoming line to be drawn out. You may consider purging the gas line at the clean out cap where the gas line enters the furnace. However, it should have restarted and stayed running after just a few times at the most because as long as the line was NOT disconnected from the main tank, there should be NO air inside the line to cause flame failure.
I'd suggest asking the service company to double check the furnace manifold pressure to ensure there is not a regulator related problem.
Three times this winter (on the coldest days no less) a tiny droplet of water froze internally of the regulator right on the orifice blocking gas flow.